Radio receiving system



Aug. 6, 1929: G. von: ARCO 1723,451

RADIO -RECEIVING SYSTEM Filed April 9, 192

INVENTOR GEURG V'0N RRC(J TORNEY Paten'ted Aug. 6, 1929.

UNITED STATES 1723,451 PATENT OFFICE.

GEORG VON ARCO, OF BERLIN, GERMANY, ASSIGNOR '1O GESELLSCHAFT FR DRAHT- LOSE TELEGRAIHIE M. B. H., 01 BERLIN, GERMAN Y, A CORIEORATION OF GERMANY.

RADIO 'RECEIVING SYSTEM.

* Application file'd April 9, 1925, Serial N0. 21,781, and in Germany April 10, 1924.

My invention relates broadly to radio receiving systems in whieh signalling energy is picked up fron1 the ether by suitable means and made t0 operate a suitable indieator.

More specifically my invention relates to radio telephony and to an a1rangemeht wherebv the troublesome eifects of static is lessene.

An object of the invention is t0 provide an arrangement of this kind which will eliminate, er greatly lessen, the eflects 0f the type 0f static which sets the receiving circuits into oscillation ab their natural frequencies.

Other objects Will be apparent from the following description anc1 claims when con- Sidered with the accompanying drawing in Which the single figure represents one of the embodiments of my invention.

It is 'Well known that by the transmission of. the carrier wave 'of the sending station to the receiving apparatus, atmospheric disturbances, i. e. the'impact-excited oscillations of-the'oscillator receiving circuits, are cousiderably ampli ed in the latter. This fact becomes most clearly noticeable When it is 0b- Served 110W suddenly these disturbances vanish when a= tran smitter non-rnodulated by 'speech, to which the receiving apparatus 'is tuned, is being disconnected.

The subject matter of the present invention aims at* eliminating these si1oek-excited oscil latory phenomena in receiving apparatus by connecting with the receiving aerial a cathode tube by what is known as negative regenerative coupling. If the receivifig antenna is tuned to the carrier frequency, am]. if a 0ertain amount of negative regenerative coupling is provided and inserted, the atmos pheric disturbanees suddenly disappear.

It is known that the transmission active in telephony takes place 0n side bands which result by addition and subtraction 0f the various acoustie frequencies from the fundamental carrier frequeney.

The receiving apparatus conforming with the present invention therefore, apart from the tuned antenna provided with negative regenerative coupling, is furnished with a secondary eircuit ehatacterized by 10W ldsses and in loose coupling relationship with the aeria1, said secondary cireuit being tuned, not t0 the carrier fre uency, but rather to a convenient value ineir e 0ne of the two sideband frequencies. These side frequencies, since they depart i'r0na the tuning, produce New, in order toobtain the iu1l intensity of transmission, the carrienfrequency, at a suitable place, is again supplied t0 the receiving a'pparatus by means of a local enerator in well-known manner, this being one in such a way that therebjr as favo'fable an aCoustic reproduetion es possible is realized. Forinstance, in case of a transmitter which does not work perfectl proportional for all acoustic frequencies, t e 10W acoustic frequencies mav be especially amplified.

Making reference to the drawing whieh forms a part of my disclosure, A represents an antenna circuit which is tuned by means of condenser 8 to the carrier frequency )t 0f the receivedwave. Closely coupled with the antenna ci1cuit A are the oseillatory circuits S and S which are so connected as to ive a reversed feed back to the antenna. 1 1e oscillatory cireuits S S are tuned to the 'carrier' frequency by means of tuning condensers 6 and 4 respectively and are connected through an electron tube R and are inductively and clos'ely coupled with the antenna eircuit at 7, as above stated through coils 5 und 3. The nature 0f the coupling is so selected that with the antenna circuit tuned t the carrier frequeney, the oscillatory circuits work to increase damping rather than to deerease it at the earrier frequency..

'Ihe true receiVer f0r the system is the tube R The receiving circuit f0r the tube R is a 10W loss circuit coupled to the antenna circuit A at 9 through coil 1 and is tuned t0 the frequency of one ofthe side bands', for exam1le, of the carrier frequency by meai1s of tuning condenser 2. By accurate tuning 0f the antenna circuit A and oscillatory c ir- 1 is therefore evident from the above arrangement that the locally generated carrier frequenc together with the side band above referre to will be impressed in the tube R While only a single'embodiment has here been shown it will be evident that nunierous other modifications of the broad idea. will occur to persons skilled in the art withoutdeparting from the spirit of the invention es recited in the appended claims.

Havmg described my invention, I claim: l. In a s1gnalling system wherein Signals are transmitted by means of a modulated high frequency carrier wave, energy transferring means tuned to the carrier frequency, a negative regeneratively coupled tube circuit coupled thereto andtuned to said carrier 'frequency and an indicating circuit loosely coupled to said energy transferring means und tuned approximately to thefrequency of one Qf the side bands accompanying sa;id carrier frequency and an oscillation genera tor couPled to seid indicator cirouit.

3. In areceiving device for a signalling system wherein signal's are transm1tted by Ineans of a modulated high frequency wave, energy transferrihg means tnned to the carrier frequeney a negative regeneratively coupled tube circuit coupled thereto and tuned to said carrier frequency', an indicating circuit coupled t0 said energy transferring ineans' and tuned' approximately to the freguency of one of the side bands accompany- 1ng said carrier frequency. and a local oscillator for supplying said indicating circuit with oscillations a pproximately equal in frequency to the carr1er wave frequency.

4. In a. signalling system W-herein signals are transmitted by means of a modulated high frequency wave, energy transferring means tuned to the carrier wave, carrier fr'equency damping ineans comprising a reversed feed back circuit closely coupled with said energy transferring means, and a radio frequency receiving circuit coupled to said energy transferring mezlns and tuned approximately t0 the frequency of one 0f the side bands accompanying said carrier frequency and means f01 impressing thereon 0scillations of approximately the same frequency as the carrier wave frequency.

5. In a, signalling system wherein signals a e trens1nitted by means oif a modulated high frequency wave, energy transferring means tuned to the carrier fre nency 0f the transmitting station from whic signals are received, a reversed feed back circuit closely coupled with said energy transferring means, said feed back coupling being adapted to selectively dzunp the carrier frequency, a 10W loss intermediate circuit loosely coupled with said energy transferrin means, seid 10W loss intermediate circuit be1ng tuned to the frequency of one bf the side bands accompunying said carrier frequency, and means associated with said intermediate circuit f0r reimpressing the currier frequenc upon the same, said intennediate cix cuit be1ng adapted t0 receive a. signal substantially the same as originally transmitted und free from static disturbances.

6. In a signalling System wherein signals are transmitted by 1neans 0f a modulated high frequency wave, energy transferring means tuned t0 the carrier wave, carrier frequency darnping means c oupled thereto, an indicating circuit coupled t0 said energy transferring means and tuned approxinmtely t0 the frequency 0f one of the side bands accompanyingsaid carrier frequency, und a local oscillator coupled to said indicating 90 circuit.

7. In a signalling systern wherein signals are transmit-ted by means of a mqdulated high frequency wave, energy transferring means tuned to the carrier wave carrier frequency damping means including a reverse feed back circuit coupled to said transferring means, and an indicating circuit coupled to said energy transferring means und tuned approximately to the frequency of one of the 100 side bands accompanying said carrier frequency.

8. In a. signalling system wherein signals are transmitted by means 0f a modulated high frequency wave, energy transferring 1neans tuned t0 the calrier wave, carr1er frequency damping 1neans coupled thereto, und a 10W loss indicating circuit cmipled t0 said energy transferring means und tuned approximately to the frequency of one of the side bands accompanying seid carrier frequency.

9. A method 0f eliminnting static disturbances during radio reception which consists in collectii1g modulated signal cnorgy 0f a 5 predetermined carrier frequency, damping said carrier frequeney with local oscillations having a frequency equal t0 the carrier frequency, and simultaneously detecting one of the side bands of said carrier frequoncy f01 12q recept-ion.

enone m ARCO, 

